1. Age: Some tumors tend to occur in specific age groups, so the patient’s age is important in the diagnosis. For example, most giant cell tumors occur after the growth plate has healed and rarely occur before the age of 20. Simple bone cysts occur almost exclusively in long bones before bone maturation. Aneurysmal bone cysts are most often seen before the age of 20 years. Langerhans granuloma is most often seen before the age of 10 years. Primary osteosarcoma occurs in adolescents. Myeloma and metastases usually occur after 40 to 50 years of age. Some tumors have a tendency to occur in specific bones and specific sites: giant cell tumor occurs in the joint end of long bones immediately adjacent to the joint surface; chondroblastoma occurs in the pre-mature epiphysis of long bones; osteosarcoma occurs in the epiphysis of long bones; E wing tumor occurs in the diaphysis; myeloma occurs in the red marrow area of the mid-axis bone. Simple bone cysts are located in the center of long bones; aneurysmal bone cysts, mucinous fibroma of cartilage, non-ossifying fibrous tumor, and giant cell tumor are mostly eccentric in growth. 3.Single or multiple: Generally single, multiple benign are seen in osteochondroma, endophytic chondroma, Langerhans granuloma and angiomatosis. The malignant ones are seen in myeloma, metastases and lymphoma. 4. Margins of lesions: This is important to determine rapid growth or slow growth. If it is not a thin edge but a wide sclerotic zone that gradually overtakes normal bone, it is not a tumor but a characteristic of inflammation; if it is fast growing and aggressive, the edge is unclear and worm-like or infiltrative, which has qualitative significance for malignant tumors. bone, bone, cartilage, mucus and collagen material, etc.), X-ray can usually only show osteogenesis and calcified cartilage. In the case of osteogenesis, benign shows regular and structural bone trabeculae (bone texture); malignant shows structureless villi, cotton balls and cloudy high-density shadow called tumor bone, which is an important basis for diagnosing osteosarcoma. Cartilage calcification then shows popcorn, dot, arc or small ring-like calcification, which can be inferred as tumor of cartilage origin based on this performance. X-rays of cysts show structureless translucent areas (MRI can infer their composition). Fibrous tissue, other cellular components, and cartilage without calcification are also not revealed on X-ray. Normal tissues can appear repair response to the destruction of tumor tissues, and this repair sclerosis change is reaction bone rather than tumor bone, and the two have different significance. 6.Destruction type: Bone destruction is not only the direct effect of tumor cells, but also the consequence of combined factors such as tumor enlargement and compression and normal osteoclast osteoclastic effect. The type of destruction can reflect the growth rate and manner of tumor, and there are several types of map-like, etched and infiltrated. Map-like is uniform and consistent destruction with clear sides, which is typical of chronic growth benign lesions; erosion-like is small multiple irregular grape-like; infiltration-like is unclear fine speckle shadow. The latter two are malignant signs of rapid growth with invasive infiltrative growth characteristics. Osteomyelitis can also appear this sign, to pay attention to the distinction. 7, periosteal reaction: usually divided into continuous and intermittent two kinds. Continuous is a solid high-density layer of periosteum with variable extent, which suggests a prolonged benign process, such as osteoid osteoma, chondroblastoma, non-tumor lesions such as bone marrow osteomyelitis, Langerhans granuloma may also appear. These suggest malignant changes, but highly aggressive non-malignant lesions can also have this appearance. 8. Soft tissue: There are soft tissue masses that are almost constant indicating aggressive lesions. Benign chondroblastomas, giant cell tumors, and aneurysmal bone cysts can sometimes present as small soft tissue masses, however, large soft tissue masses can be considered an important sign of malignancy. A large soft tissue mass with only small bone destruction would indicate that the bone is secondary to the invasion. The above contents are important materials for the diagnosis and differential diagnosis of bone tumor, and should be applied comprehensively and holistically.